The objectives of this project are to identify and describe environmental and host determinants of cancer in areas at high risk of cancer through the use of analytical epidemiologic and biometric techniques, particularly case-control studies of specific cancers. A case-control study of renal cancer continued during the year in Minnesota, which leads the nation in rates of this malignancy. The study will evaluate the role of diuretics, widely-prescribed medications recently linked to renal tumors in experimental animals. A parallel international investigation in northern Europe and Australia also was begun. Data analyses from a large multicenter study of oral cancer showed that use of mouthwashes high in alcohol content may increase risk, consistent with the well established increase in risk of these cancers associated with drinking alcoholic beverages. Protective effects were found for diets high in fresh fruit and vegetable intake among both blacks and whites, but somewhat lower levels of consumption may contribute to the high rates of oral cancer among blacks. In studies in high-risk areas overseas, fruit, fresh vegetables, and vitamin C and E intakes were associated with reduced risk of both intestinal and diffuse type stomach cancer in Italy. Dietary patterns help account for the markedly lower risk of this cancer in southern Italian provinces. In China, air pollution from home heating and cooking was found to contribute to the elevated rates of lung cancer in Shenyang, but no effect of indoor radon was detected. Vitamin/mineral intervention trials continued in Linxian, a rural Chinese county with the world's highest rate of esophageal cancer, as did an investigation of the determinants of gastric precancerous lesions and their rates of transition to stomach cancer in Shandong Province.